Fun fact, there are only 3 trillion trees left on the Planet, so adding 10 billion actually normally would have an impact. However, Brazil is set to cut down 10 billion trees, so it evens out, I guess.
The problem that the world faces is that people are cutting down more trees than we are planting. If the governments of the world are serious about preservation, more needs to be done to regulate the lumber industry. Pakistan shouldn't just plant 10 billion trees, it should make it mandatory for a certain amount of trees to be planted every year, and clamp down on illegal cutting down of trees. For every house built, make property developers plant 2 trees; For every small park, plant 50; for every apartment building built, plant 100.
The end goal of both Pakistan and India should be to plant a combined trillion trees by 2050, across South Asia.